Digital Memory Versatility of Fully π-Conjugated Donor–Acceptor Hybrid Polymers

Abstract

The fully π-conjugated donor-acceptor hybrid polymers Fl-TPA, Fl-TPA-TCNE, and Fl-TPA-TCNQ, which are composed of fluorene (Fl), triphenylamine (TPA), dimethylphenylamine, alkyne, alkyne-tetracyanoethylene (TCNE) adduct, and alkyne-7,7,8,8-tetracyanoquinodimethane (TCNQ) adduct, were synthesized. These polymers are completely amorphous in the solid film state and thermally stable up to 291-409 °C. Their molecular orbital levels and band gaps vary with their compositions. The TCNE and TCNQ units, despite their electron-acceptor characteristics, were found to enhance the π-conjugation lengths of Fl-TPA-TCNE and Fl-TPA-TCNQ (i.e., to produce red shifts in their absorption spectra and significant reductions in their band gaps). These changes are reflected in the electrical digital memory behavior of the polymers. Moreover, the TCNE and TCNQ units were found to diversify the digital memory modes and to widen the active polymer layer thickness window. In devices with aluminum top and bottom electrodes, the Fl-TPA polymer exhibits stable unipolar permanent memory behavior with high reliability. The Fl-TPA-TCNE and Fl-TPA-TCNQ devices exhibit stable unipolar permanent memory behavior as well as dynamic random access memory behavior with excellent reliability. These polymer devices were found to operate by either hole injection or hole injection along with electron injection, depending on the polymer composition. Overall, this study demonstrated that the incorporation of π-conjugated cyano moieties, which control both the π-conjugation length and electron-accepting power, is a sound approach for the design and synthesis of high-performance digital memory polymers. The TCNE and TCNQ polymers synthesized in this study are highly suitable active materials for the low-cost mass production of high-performance, polarity-free, programmable, volatile, and permanent memory devices that can be operated with very low power consumption, high ON/OFF current ratios, and high reliability.

Nonvolatile Tri‐State Resistive Memory Behavior of a Stable Pyrene‐Fused N‐Heteroacene with Ten Linearly‐Annulated Rings

“…Yet, the negative ESP regions (in blue A and B) arisen from the pyrazine and benzothiadiazole (BT) also exist. These negative regions could act as “trap” sites to impede the field‐induced transfer of charge carriers . Under a low voltage bias, charge carriers hardly get enough energy to overcome the injection barriers between the donor and acceptors.…”

The [2+2] Cycloaddition‐Retroelectrocyclization (CA‐RE) Click Reaction: Facile Access to Molecular and Polymeric Push‐Pull Chromophores

“…Thef irst reduction potential (E red,1 )o rthe LUMO energy level decreased as more TCNE was added ( Figure 13). [113] Thes ame polymer could also be postfunctionalized by aC A-RE reaction with TCNQ to yield P16 ( Figure 14). This finding was strongly associated with device performances.B ottom-gate top-contact-type thin-film transistors (TFTs) based on P14 and P15 were fabricated and their performances were evaluated.…”

Azulene‐Based Donor–Acceptor Systems: Synthesis, Optical, and Electrochemical Properties

“…[14] Yamashita and co-workers reported that alkyne derivatives with a1 ,3-dithiol-2-ylidene moiety reactedw ith TCNE to give TCBD derivatives that showed amphoteric redox behavior in cyclic voltammetry (CV). [17] They also investigated their applicationsa si on sensors using polymere ffects, digitalm emory, [18] and photovoltaic devices. [16] Michinobu et al demonstrated that polymers embedded with TCBD units showeda nI CT absorption band with al ow energy band gap.…”